No problem, thanks indeed. I had recently implemented this nicer error dialog where it was an ugly access violation earlier. Just I was a bit unsure about the phrasing. Do you think I should rephrase that?

HeidiSQL wrote: Can't find a usable libmysql.dll. Please launch xyz.exe from the directory where you have installed it.

No, HeidiSQL definitely needs a fitting libmysql.dll . This can also be one somewhere in your Windows directory or in the path environment, but if you never installed one then you need the HeidiSQL installer once.